Field of the Invention
The present invention relates to a method for making a coated cardboard container configured for the packaging of asphalt. The asphalt may be filled hot, in a molten state, and it then solidifies within the container. The container acts as the shipping medium through which the asphalt is transported to its end user. At the end user of the solidified asphalt the container may be easily peeled away from the solidified asphalt leaving a conveniently sized and shaped solid block which is suitable for further processing.
Description of the Related Art
Asphalt is used for many purposes, such as roofing or road work. Asphalt is typically made in one location then packaged and shipped to the end user for use. Asphalt is typically prepared hot, poured into a container and then allowed to cool and solidify. The cooled asphalt is solid, but still sticky to the touch. The container allows the asphalt to be handled and shipped. Without the container the blocks of asphalt would adhere to each other. The common methods of packaging hot asphalt currently in use require the asphalt producer to have machinery. This machinery may be needed to cool the asphalt prior to dispensing into a packaging material, for shaping the asphalt prior to packaging, for enveloping the asphalt in a packaging material or to assist in assembling a container into which the asphalt may be filled and packaged.
There are a number of patents for asphalt containers. U.S. Pat. No. 2,310,712 to Schmied discloses a boxed lined with film or coatings to contain asphalt poured hot into the box. The coating prevents the asphalt from adhering to the material of the box. U.S. Pat. No. 2,760,629 to Thagard discloses a cardboard tube placed on a separate base for holding asphalt. The tube is constructed by stitching the sides of the tube together and then stitching the bottom on to the end of the tube. U.S. Pat. No. 3,366,233 to Roediger discloses a specially lined bag for holding and transporting asphalt. The interior lining is made up of a heat resistant film. U.S. Pat. No. 5,452,800 to Muir discloses a box lined with a special film that allows asphalt to harden into uniform blocks for ease of shipping. Asphalt is most commonly transported in cardboard of fiber drums, or tubes, having a metal bottom adhered to the end of the tube.
Manufacturers of Built Up Roofing or BUR asphalt, who need to pack their product in a container with a capacity of 50 lbs to 100 lbs to meet market demand, and who do not wish to use slower production methods involving molding a block of asphalt and then wrapping it in plastic film, are almost exclusively using a two piece keg consisting of a coated cylindrical cardboard sleeve and a circular metal base. The two components of the keg, the lined cardboard sleeve and the round metal base, are supplied in flat form to the asphalt manufacturer who then needs a special machine to crimp the circular metal base to the cylindrical cardboard sleeve in order to form the keg. This method is time consuming and labor intensive. The machinery for crimping the metal base and attaching it to the cardboard sleeve is prone to malfunction, and when it fails it requires specialist engineers to make repairs, which is costly and inconvenient. In cases where the metal base does not crimp satisfactorily to the cardboard sleeve the keg will malfunction and asphalt will leak out, causing disruption and product loss. Unfortunately it is often difficult to determine whether the leakage is due to a faulty crimping process which adhered the metal base to the cardboard sleeve, or to faulty components. This makes it hard for the asphalt manufacturer to determine how to fix the problem. The fact that the keg has a metal base is also a disadvantage for the end user for a number of reasons. First it can make removing the asphalt from the packaging more difficult due to the asphalt adhering to the metal base. Second the metal base can have sharp edges, which can cause injuries to workers trying to remove the asphalt. Finally, it makes disposal of waste more difficult because of the metal component.